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CHAP, xvr                    THE   HEDGEHOG   FAMILY                            509

There is, furthermore, a distinct tendency towards a dis-
appearance of functional milk teeth, which is best seen in
Sorex, where there are only seven milk teeth, none of which ever
cut the gum. This suppression of the milk dentition is like that
of the Marsupials, Edentates, and Whales, all of which appear to
be—the first certainly are—ancient forms of mammalian life.

There is also a fairly well-defined, though shallow, cloaca in
many genera. Finally, the testes are purely abdominal in some,
and in none is there a full descent into a scrotum, as in the more
highly-developed Eutheria.

Fam. 1. Erinaceidae.—This family contains the genera
jErinaceus, JEfylQinys, and Gfj/7nnura.
Sylomys, considered by Dobson to fall within Gymnura, is
kept separate by Leche.1 H, suillus is a Malayan animal, small in
size, about 5 inches long, with a short tail. Like Gynmura, it is
spineless. The ears are decidedly large and nude. There is one
pair of inguinal and one pair of thoracic teats. The colour
above is a rusty brown with yellowish-white under parts. The
palms and soles are quite naked. In its general form it recalls
Tupaia, very much more than its own immediate relatives.
There is no doubt, however, of its systematic position when the
skeleton and teeth are examined. A variety has been described
from altitudes of 3000 to 8000 feet on Mount Kin a Balu in Borneo.
It has the complete dentition of forty-four teeth. There are
fourteen pairs of ribs. As in Gymnura, the tibia and fibula are
united below. The genus is considered by Leche to be the oldest
existing type of Erinaceidae.
Gymnura2 is also a Malayan form with the complete dentition
of the last, but with fifteen pairs of ribs and a longer tail, con-
sisting of twenty-three vertebrae as against fourteen. There is,
as with Hylomys, but one species, Gr~ rafflesii. This animal has
a peculiar odour, resembling decomposed cooked vegetables.
1   " Bemerlcungen   iiber   die   Genealogie   der  Erinaceen."       In    Festschrift  f.
Liljeborg, 1896.     See also Anderson, Trans. Zool. Soc. vili. 1874, p. 453.
2  Dobson, "Notes on the Anatomy of the Erinaceidae," JProc. Zool. Soc, 1881,
p. 389.